Further to the post on the new JBEC CNC router system availabe in the UK
The following is some information for those interested in under the bonnet inspections. Apologies this has taken longer than expected. Not enough hours in the day and I wanted to do it right and be as comprehesive as possible in the hope that on day in the next decade we get the JAZZCNC seal of approval :)
Right - here goes...
So the pictures are all from our JBEC 604012 model shown below in Figure 1.
Figure 1. - JBEC 604012
Figure 2. shows the main components of the main drive system used to traverse the main gantry. The design is based on two rails mounted on the opposing faces of the main machine bed frame. Two slide rails, each consisting of two rolling element bearings (discussed further below) sit on the two rails and provide the required stiffness in all directions except the direction of motion where the slide moves freely with minimal friction.
Figure 2. Gantry structure design overview
Figure 3 shows the top slide rail mounted and bolted to the main side aluminium panel. A second inside panel covers the assembly shown and increased the torsional stiffness of the frame as it is shown. Shown also is the ballscrew encapsulation at the opposite side to the motor.
Figure 3. View of the slide rail mounted on the bed.
Figure 4, shows the mechanism used to transfer the drive from the ballscrew carriage to the bottom slide rail. Note the 5 bolts in the mouing system connected to the slide rail. The 4 outside bolts fasten the aluminium panel to the slide for the drive transfer. The middle bolt is used to tune the gantry position - and is discussed further below.
Figure 4. Bottom rail and drive system assembly
Further to Figures 3 and 4, Figure 5 shows the linear slide disconnected from the slide rail. Shown are the rolling elements used to interface with the slide rail. Note also the tuning block connected with the tuning bolt shown in Figure 4.
Figure 5. Image shows the exposed rolling elements
Figures 6(a) and (b) show the linear slides composition with the rolling element shown. The rolling elements are supported on both sides and have two internal bearings. Not also the trough in the rolling element that allows some leeway for swarf and other possible contamination getting into the drive system.
Figure 6 (a). Top linear slide rolling elements
Figure 6 (b). Showing how the slide system assembles together.
Figure 7(b) shows the gantry side aluminium panel and shows the two bolts fastened to the tuning block as shown in Figure 5 and Figure 7(a). The 4 other holes shown are slotted to allow the tuning bolt to be used to adjust the slide setup. Once tuned and adjusted the holes are fastened and the gantry is ready for final assembly. The system is modular and therefore easy to change, service and tune long term. The result is a very stiff structure that provides excellent support in all directions apart from the direction of motion where linear almost frictionless travel can occur
Figure 7 (a). Bottom slide assembly setup
Figure 7 (b). Side panel for drive tuning
Figure 8 shows the extra aluminium side brace installed to provide extra stiffness through from the ball-screws into the gantry tower.
Figure 8. Stiffening plate
Figure 9 shows the two ballscrews used to drive the gantry structure. Both the side pillars therefore have their own drive mechanism from each of the two ballscrew carriages. Figure 10 shows the cable management under the machine bed used to transfer the drive motors and spindle cables up into the gantry tower structure. Figure 11 shows the drive distribution from the stepper motors to the two ballscrew pulleys driving the two Y axis ballscrews.
Figure 9. Dual ballscrew drive
Figure 10. Cable management under machine bed
Figure 11. Belt drive to the two ballscrew pulleys.
Figure 12 shows an overall view of the Z axis slide and drive mechanism. As shown the upper and lower z axis guides are spaced apart such that they are located in the same locations on the gantry as where the X axis slide mechanism mounts on the main X axis slide rails. This is further illustrated in Figures 13 and 14. Figure 14 shows how the ballscrew drive will transfer force directly at the same location as the main X axis carriage system, and from there directly into the X axis guide system.
Figure 12. View of the X axis mechanism fully assembled
Figure 13. Close up of the left hand side upper prismatic guide
Figure 14. shows how the process forces are translated into the gantry tower structure.
If ever you are put in front of a CNC router system you are about to part cash with. I would ask every customer to look at this aspect of a machine as it plays a core role in the machine performance. If you grab the spindle structure (not too hard in case you break it before you've bought it :) ) and put some pressure on the structure in all directions and see how it performs. What your doing essentially is simulating a cutting process where you are putting forces on the machine. The level of "play and delfection" will dictate the performance.
You will pull the machine off the table before you bend and flex the gantry structure with any significance on this platform.
Figures 15 and 16 shows the control electronics. She runs on a 48V PSU matched to the oriental motors specs running each of the three axes. There is a BOB for the LPT logic distribution from the PC side and there is a 12V relay board for the user interface buttons on the machine control panel. Figure 17 shows the innerds of the machine control panel. The latched start, stop, Estop and spindle on/off override switch are all operating safely on 24V running back to the relay card. 230V AC comes in and up through the machine for the spindle only and does not come through the control panel.
Figure 15. System electronics
Figure 16. AC in and LPT connection and 4th axis connection.
Figure 17. Control panel work
Figure 18 shows our USB controller that we have adopted as standard thanks to CNC drive electronics. We now offer a range of CNC drive electronics with more information coming soon.
Figure 18. USB machine control
High res image link here JBE CNC router design - a set on Flickr
JAZZ - that okay? Not to much waffle I hope. I've tried to keep it clear and concise?
Last edited by StoneyCNC; 15-08-2013 at 05:58 PM.
Oh dear . . Oh dear . . .Oh dear what do I Say.?????? . . . . . . No Sorry can't give approval.!!
First let me say not going to pull it apart or condemn because the machine is very well thought out and professionally put together. far far removed from like of strike CNC and some other 'Merchant's' that are dicey.! . . . I congratulate on the professional way it's done and presented.
What bothers me is the the fact you have what is basicly just a supped up version of skate board bearings coupled with very flimsy gantry sides connected to flimsy ballnut brackets. Now for £5100 for machine and Electrics only, I would expect much more for my money with real profiled linear rails and substantial frame.
With this rail system and weak frame work I foresee that this machine will be very baggy within side 3yrs if worked 8hrs day and will require plenty of maintenance and setting up to keep accurate much after the newness has worn off.!!
Personally for best part of 6k investment with PC, spindle etc I'd want better than this machine provides. That said for Hobby use then it's rail system and IMO weak gantry are fine, It's just far too expensive.!!
Very nicely done thou and very professional and you seem a very straight guy so I wish you all the best with this machine.! . . . But for what it's worth I Honestly can't give 100% approval at this price. . . Sorry.
Last edited by JAZZCNC; 15-08-2013 at 06:56 PM.
I agree that the ballnut mounts in particular look much too thin, and that for the amount this costs you should be getting proper linear guides not glorified skate bearings.
If I was buying a CNC router I'd take a dial indicator, a force meter (e.g. cheap hanging scales would do) and a piece of string with me, then use them to do, at the very least, the following tests:
- Set the dial indicator up to measure the deflection in each axis and apply a suitable force, divide the two readings to find the stiffness of each axis and compare that to typical values or other machines.
- Use the indicator to check the backlash of each axis. For any machine that uses ballscrews and is set up correctly, the backlash should be less than about 0.05mm in X and Y. If Z uses rails with low preload, the backlash should be close to zero as gravity pre-loads the axis. If it isn't then that implies the rails and ballscrew could be misaligned.
- Again set the indicator parallel to each axis, and give each axis/slide/ballscrew a sharp tap. The indicator needle will oscillate and should return to zero (+-backlash). If it doesn't return to zero then something's loose or the ballscrews aren't mounted properly. If the indicator oscillates for a long time before returning, then I'd be concerned that the machine will resonate when cutting.
- With the indicator in the spindle, put a large mass on the machine bed (e.g. sit on it), and see how much the bed deflects.
- Mount indicator in spindle on L-shaped bar and use it to check the spindle is in tram. This is less significant than the other points, since you should be able to correct it without too much difficulty, however it's a good sign of how carefully the machine has been built
Feel free to post a video showing these tests, I expect you've already checked these things so it shouldn't be a problem?
Last edited by Jonathan; 15-08-2013 at 07:33 PM. Reason: Formatting
Jazz - haha - how naive of me to seek approval so early in the debate
So in short - from your message one can summarise the following
- The linear slides on our machine are "Micky mouse"
- The gantry is thin and has poof stiffness - made from chewing gum
In light of the above points - "Very nicely done thou and very professional and you seem a very straight guy" would not suggest what the above points do in that "actually the machine is poor and its not good value for money - i.e we are ripping people off"...
I fully appreciate that this is a public forum and that by posting here it is totally up to everyone to say it how they see it - to be honest that is why I'm here... And I like the pointed discussion! However heated
JBEC and us could not offer the machine platform at the prices we do were it not for the volume of work going on with the German supplier of our sub assemblies. This is the only way we can keep costs down and to offer the machines at the prices we do. If someone could produce a platform in volume, supply and support it, offer it at lower prices and atill have a business model at the end of the day then hats off to them!
Your comments JAZZ (which are welcomed and respected in light of what I've seen on this forum and your portfolio of CNC work which is impressive) would therefore imply that 30 years of experience in the automotive industry through JBEC and 20 years of experience in machine building from our German colleagues have come together to produce a micky mouse machine that - "looks professional" but really is not up to much.
It would also go against what our customers in Ireland have been saying - in particular a customer who has been machining bog oak all day every day for well over a year now. I can see can I get details on the exact machine conditions that have been in service that long? Your comments related to the machine requiring lots of TLC to keep her in check are not echoed by our growing customer base here in IRL.
We are not trying to provide a machine like a Hurco/Bridgeport/Metal milling machine that will eat any DOC in Ali Steel and stainless for breakfast lunch and dinner. I would plea here for some relativity. This is a CNC router platform up to soft metals. Your reference to 12mm diam 3-4mm DOC in Ali is well IMO not a good parameter set for a machine in this Market sector? If someone came to me with those specs - I'd tell them to go look at a bridgeport/hurco/semco etc etc - We would not support a router operating in those conditions!
Relative to the competition in this price range and performance envelope, and relative to our experience with the competition we would strongly disagree with the sentiments here... I'm here to bash competitors as everyone is entitled to compete in a growing market - but I would plea for some standardised relativity - which as per below Jonathan has kindly provided.
Also - on the cost front - The total cost of owner ship has to be considered. Locally supported with follow up help. You are not just buying a hair-dryer
And 100% if you put our system up against a metal milling machine then yes 100% the slides are not fit for purpose and the gantry is made of chewing gum! Also - anyone who is clued in and has access to fabrication facilities could indeed put together a platform with more performance for less... not accounting for the time, design and nouse to do it. Volume production, installation and follow up support to run a business are, as I'm sure you know, a different story.
If someone could build, supply and support a machine to the same quality level as use then I want to see it!
And yes again - profiled rails TKH, HIWIN etc are phenomenal pieces of hardware! And when I first saw that particular slide design concept I was also initially sceptical. However - the Germans know what they are at and I have been proved wrong!
I have worked on some other low cost routers and a manual nudge of the axis is a quick fire way to sus out if there is any potential stiffness in there at all.
In full agreement with you there - this is a much better and standardised method for machine analysis. But in reality how many customers who ended up buying something like the Strike CNC would do this? Or even know how to do this?
Fancy throwing some figures out there? typical machining lets say a hardwood at moderate feeds? Lets throw some Newton values out there.......
Will gather media of other axes also.
Perhaps other players could look to do the same?
The questions raised here are exactly what we all need potential CNC customers to be considering and asking - and in general this doesn't happen. Hence I guess how Strike could make sales. It is hard as I was once a noob to CNC myself and I didn't ask these questions when I bought my machine...
Thanks for the feedback guys - all welcomed!
Time is a great healer it's also great test of greatness and killer of crap so we'll see what we see in 3yrs time.!!
Yes agreed and that comment wasn't aimed at this machine but the reference you made before about making a machine capable of cutting Aluminium.!. . . Now there's scratching and there's cutting this machines a scratcher if you want a cutter then this machine in a uprated form just ain't going to cut it.!!
EXEL CNC SL6090 Pro
Last time I knew (2yrs ago) they were asking about £5 -6K for same size has your 5.2K machine with Hiwin linear rails, Gecko drives etc all very neatly done.
Purely coincidentally the machine frame is very very similar to a machine I've made for few years now and designed well before they started selling these so I know exactly how strong this design is and can tell you with 100% confidence it will knock the spots off yours in terms of strength.
HD profile and 20mm aluminium gantry sides also knock the spots off 5-6mm aluminium sheet anyday.!! . . . The linear components speak for them self and you'd be foolish to try and compare your linear bearing effort against them.!
Gecko drives are quality units and Equal to lead shine DM series drives.
Like I say not Bashing just for sake of it or saying it won't do it's intended role, just pointing out it could be better given the relatively high price.!
Again compliment your honesty and professionalism also wish you well and success.! . . . Now crack on selling making chips.!!
Anyone looked at that Exel website lately ?, some links don't work, the info is sparse to say the least, no prices, problems ?
Can't see any problems with that and end of the day if your spending 5-10K you'll want to be at least speaking to someone or better still seeing real thing not buying going on pictures off web site.!
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